1. Field of the Invention
The present invention relates in general to a vehicle braking system and, more specifically, to a power management system for a vehicle braking system having electromagnetic and friction braking.
2. Description of the Related Art
Hybrid braking systems for vehicles are well known. These braking systems usually include electromagnetic and friction braking capabilities. The use of electromagnetic braking improves efficiency in vehicles by recovering kinetic energy produced by the vehicle with an electric machine. The electric machine generates electric energy that is applied to electromagnetic retarders (also referred to as eddy current devices) within the braking system. In some instances, the electric machine generates an amount of power in excess of the amount required by the eddy current devices. When this occurs, prior art braking systems have disclosed methods of recovering the excess energy to power other components or to charge the vehicle battery. However, these prior art systems have proved to be costly and largely inefficient. Further, the determination of whether a surplus of power is available from the generator requires additional hardware.
It would therefore be desirable to provide a hybrid braking system that reduces the amount of hardware and efficiently distributes the energy generated within the braking system thereby utilizing any excess energy generated by the generator to charge a supplemental power source such as a battery.